This project is seeking to develop a prosthesis for the lower urinary tract that will provide for urinary continence in patients with neurogenic bladders or whose mechanisms of continence have been destroyed by trauma or surgery. This prosthesis is to be intraurethral and will be able to be changed without surgery when encrustation occurs. Two types of prostheses are under consideration. The first will be used in conjunction with intermittent catheterization and the second will open and close itself to permit voiding when appropriate without the need for catheterization.